Midterm exams are finally over, leaving some students overjoyed and others depressed, and now it's time to decide who will participate in which events at the school's upcoming athletic festival. Riri is selected as the anchor for the swimming event, but Erika nominates Komichi for the same position, so the two girls compete to determine who will be the anchor. Riri is a member of the swimming club, and once made it to nationals in elementary school, and Komichi feels no desire to compete against her as rivals. Then Riri proposes that if she wins, she and Komichi should swap uniforms...